Intravascular blood filters and methods of use

ABSTRACT

Multi-filter endolumenal methods and systems for filtering fluids within the body. In some embodiments a multi-filter blood filtering system captures and removes particulates dislodge or generated during a surgical procedure and circulating in a patient&#39;s vasculature. In some embodiments a dual filter system protects the cerebral vasculature during a cardiac valve repair or replacement procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.12/689,997, filed Jan. 19, 2010, which claims the benefit of U.S.Provisional Patent Application No. 61/145,149, filed Jan. 16, 2009, bothof which are incorporated herein by reference. This application alsoclaims the benefit of U.S. Provisional Application No. 61/244,418, filedSep. 21, 2009; U.S. Provisional Application No. 61/334,893, filed May14, 2010; and U.S. Provisional Application No. 61/348,979, filed May 27,2010, all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Thromboembolic disorders, such as stroke, pulmonary embolism, peripheralthrombosis, atherosclerosis, and the like, affect many people. Thesedisorders are a major cause of morbidity and mortality in the UnitedStates and throughout the world. Thromboembolic events are characterizedby an occlusion of a blood vessel. The occlusion can be caused by a clotwhich is viscoelastic (jelly-like) and is comprised of platelets,fibrinogen, and other clotting proteins.

Percutaneous aortic valve replacement has been in development for sometime now and stroke rates related to this procedure are between four andtwenty percent. During catheter delivery and valve implantation plaquemay be dislodged from the vasculature and may travel through the carotidcirculation and into the brain. When an artery is occluded by a clot,tissue ischemia (lack of oxygen and nutrients) develops. The ischemiawill progress to tissue infarction (cell death) if the occlusionpersists. Infarction does not develop or is greatly limited if the flowof blood is reestablished rapidly. Failure to reestablish blood-flow canlead to the loss of limb, angina pectoris, myocardial infarction,stroke, or even death.

Occlusion of the venous circulation by thrombi leads to blood stasiswhich can cause numerous problems. The majority of pulmonary embolismsare caused by emboli that originate in the peripheral venous system.Reestablishing blood flow and removal of the thrombus is highlydesirable.

Techniques exist to reestablish blood flow in an occluded vessel. Onecommon surgical technique, an embolectomy, involves incising a bloodvessel and introducing a balloon-tipped device (such as a Fogartycatheter) to the location of the occlusion. The balloon is then inflatedat a point beyond the clot and used to translate the obstructingmaterial back to the point of incision. The obstructing material is thenremoved by the surgeon. While such surgical techniques have been useful,exposing a patient to surgery may be traumatic and is best avoided whenpossible. Additionally, the use of a Fogarty catheter may be problematicdue to the possible risk of damaging the interior lining of the vesselas the catheter is being withdrawn.

A common percutaneous technique is referred to as balloon angioplastywhere a balloon-tipped catheter is introduced into a blood vessel,typically through an introducing catheter. The balloon-tipped catheteris then advanced to the point of the occlusion and inflated in order todilate the stenosis. Balloon angioplasty is appropriate for treatingvessel stenosis but is generally not effective for treating acutethromboembolisms.

Another percutaneous technique is to place a microcatheter near the clotand infuse Streptokinase, Urokinase, or other thrombolytic agents todissolve the clot. Unfortunately, thrombolysis typically takes hours ordays to be successful. Additionally, thrombolytic agents can causehemorrhage and in many patients the agents cannot be used at all.

Another problematic area is the removal of foreign bodies. Foreignbodies introduced into the circulation can be fragments of catheters,pace-maker electrodes, guide wires, and erroneously placed embolicmaterial such as thrombogenic coils. Retrieval devices exist for theremoval of foreign bodies, some of which form a loop that can ensnarethe foreign material by decreasing the size of the diameter of the looparound the foreign body. The use of such removal devices can bedifficult and sometimes unsuccessful.

Moreover, systems heretofore disclosed in the art are generally limitedby size compatibility and the increase in vessel size as the emboli isdrawn out from the distal vascular occlusion location to a more proximallocation near the heart. If the embolectomy device is too large for thevessel it will not deploy correctly to capture the clot or foreign body,and if too small in diameter it cannot capture clots or foreign bodiesacross the entire cross section of the blood vessel. Additionally, ifthe embolectomy device is too small in retaining volume then as thedevice is retracted the excess material being removed can spill out andbe carried by flow back to occlude another vessel downstream.

Various thrombectomy and foreign matter removal devices have beendisclosed in the art. Such devices, however, have been found to havestructures which are either highly complex or lacking in sufficientretaining structure. Disadvantages associated with the devices havinghighly complex structure include difficulty in manufacturability as wellas difficulty in use in conjunction with microcatheters. Recentdevelopments in the removal device art features umbrella filter deviceshaving self folding capabilities. Typically, these filters fold into apleated condition, where the pleats extend radially and can obstructretraction of the device into the microcatheter sheathing.

Extraction systems are needed that can be easily and controllablydeployed into and retracted from the circulatory system for theeffective removal of clots and foreign bodies. There is also a need forsystems that can be used as temporary arterial or venous filters tocapture and remove thromboemboli generated during endovascularprocedures. The systems should also be able to be properly positioned inthe desired location. Additionally, due to difficult-to-access anatomysuch as the cerebral vasculature and the neurovasculature, the systemsshould have a small collapsed profile.

The risk of dislodging foreign bodies is also prevalent in certainsurgical procedures. It is therefore further desirable that such embolicapture and removal apparatuses are similarly useful with surgicalprocedures such as, without limitation, cardiac valve replacement,cardiac bypass grafting, cardiac reduction, or aortic replacement.

SUMMARY OF THE INVENTION

In general, the disclosure relates to methods and apparatuses forfiltering blood. Filtration systems are provided that include a proximalfilter and a distal filter. The filtration systems can be catheter-basedfor insertion into a patient's vascular system.

One aspect of the disclosure is a catheter-based endovascular system andmethod of use for filtering blood that captures and removes particlescaused as a result of a surgical or endovascular procedures. The methodand system include a first filter placed in a first vessel within thepatient's vascular system and a second filter placed in a second vesselwithin the patient's vascular system. In this manner, the level ofparticulate protection is thereby increased.

One aspect of the disclosure is an endovascular filtration system andmethod of filtering blood that protects the cerebral vasculature fromembolisms instigated or foreign bodies dislodged during a surgicalprocedure. In this aspect, the catheter-based filtration system isdisposed at a location in the patient's arterial system between the siteof the surgical procedure and the cerebral vasculature. Thecatheter-based filtration system is inserted and deployed at the site tocapture embolisms and other foreign bodies and prevent their travel tothe patient's cerebral vasculature so as to avoid or minimizethromboembolic disorders such as a stroke.

One aspect of the disclosure is an endovascular filtration system andmethod of filtering blood that provides embolic protection to thecerebral vasculature during a cardiac or cardiothoracic surgicalprocedure. According to this aspect, the filtration system is acatheter-based system provided with a first filter and a second filter.The first filter is positioned within the brachiocephalic artery,between the aorta and the right common carotid artery, with the secondfilter being positioned within the left common carotid artery.

One aspect of the disclosure is a catheter-based endovascular filtrationsystem including a first filter and a second filter, wherein the systemis inserted into the patient's right brachial or right radial artery.The system is then advanced through the patient's right subclavianartery and into the brachiocephalic artery. At a position within thebrachiocephalic trunk between the aorta and the right common carotidartery, the catheter-based system is manipulated to deploy the firstfilter. The second filter is then advanced through the deployed firstfilter into the aorta and then into the left common carotid artery. Oncein position within the left common carotid artery the catheter-basedsystem is further actuated to deploy the second filter. After thesurgical procedure is completed, the second filter and the first filterare, respectively, collapsed and withdrawn from the arteries and thecatheter-based filtration system is removed from the patient'svasculature.

One aspect of the disclosure is a catheter-based filtration systemcomprising a handle, a first sheath, a first filter, a second sheath anda second filter. The handle can be a single or multiple section handle.The first sheath is translatable relative to the first filter to enactdeployment of the first filter in a first vessel. The second sheath isarticulatable from a first configuration to one or more otherconfigurations. The extent of articulation applied to the second sheathis determined by the anatomy of a second vessel to which access is to begained. The second filter is advanced through the articulated secondsheath and into the vessel accessed by the second sheath and,thereafter, deployed in the second vessel. Actuation of the first sheathrelative to the first filter and articulation of the second filter isprovided via the handle.

In some aspect the first sheath is a proximal sheath, the first filteris a proximal filter, the second sheath is a distal sheath, and thesecond filter is a distal filter. The proximal sheath is provided with aproximal hub housed within and in sliding engagement with the handle.Movement of the proximal hub causes translation of the proximal sheathrelative to the proximal filter. The distal sheath includes a distalshaft section and a distal articulatable sheath section. A wire isprovided from the handle to the distal articulatable sheath section.Manipulation of the handle places tension on the wire causing the distalarticulatable sheath section to articulate from a first configuration toone or more other configurations.

In some aspects the proximal filter and the distal filter are bothself-expanding. Movement of the proximal sheath relative to the proximalfilter causes the proximal filter to expand and deploy against theinside wall of a first vessel. The distal filter is then advancedthrough the distal shaft and distal articulatable sheath into expandingengagement against the inner wall of a second vessel.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary prior art catheter being advancedthrough a portion of a subject's vasculature.

FIGS. 1A-1C illustrate an exemplary dual filter system.

FIGS. 1D and 1E illustrate exemplary proximal filters.

FIGS. 2A-2D illustrate an exemplary method of delivering and deploying adual filter system

FIGS. 3-5 illustrate a portion of an exemplary delivery procedure forpositioning a blood filter.

FIGS. 6A and 6B illustrate

FIGS. 7A and 7B illustrate a portion of an exemplary filter system.

FIGS. 8A-8C illustrate an exemplary pullwire.

FIGS. 9, 9A, and 9B show an exemplary embodiment of a distal sheath withslots formed therein

FIGS. 10A and 10B illustrate a portion of exemplary distal sheathadapted to be multi-directional.

FIGS. 11A-11C illustrate merely exemplary anatomical variations that canexist.

FIGS. 12A and 12B illustrate an exemplary curvature of a distal sheathto help position the distal filter properly in the left common carotidartery.

FIGS. 13A and 13B illustrate alternative distal sheath and distal shaftportions of an exemplary filter system.

FIG. 14 illustrates a portion of an exemplary system including a distalshaft and a distal sheath.

FIGS. 15A-15D illustrate alternative embodiments of the coupling of thedistal shaft and distal sheath.

FIG. 16 illustrates an exemplary embodiment of a filter system in whichthe distal sheath is biased to a curved configuration.

FIG. 17 illustrates a portion of an alternative filter system.

FIGS. 18A and 18B illustrate an exemplary proximal filter.

FIGS. 19A-22B illustrate exemplary proximal filters.

FIGS. 23A-23F illustrate exemplary distal filters.

FIGS. 24A-24C illustrate exemplary embodiments in which the systemincludes at least one distal filter positioning, or stabilizing, anchor.

FIGS. 25A-25D illustrate an exemplary embodiment of coupling a distalfilter to a docking wire inside of the subject.

FIGS. 26A-26G illustrate an exemplary method of preparing an exemplarydistal filter assembly for use.

FIGS. 27A and 27B illustrate an exemplary embodiment in which a guidingmember, secured to a distal filter before introduction into the subjectis loaded into an articulatable distal sheath.

FIGS. 28A-28E illustrate an exemplary distal filter assembly incollapsed and expanded configurations.

FIGS. 29A-29E illustrate a portion of an exemplary filter system with alower delivery and insertion profile.

FIGS. 30A and 30B illustrate a portion of an exemplary filter system.

FIGS. 31A-31B illustrate an exemplary over-the-wire routing system thatincludes a separate distal port for a dedicated guidewire.

FIGS. 32A-32E illustrate an exemplary routing system which includes arapid-exchange guidewire delivery.

FIGS. 33-35 illustrate exemplary handle portions of the blood filtersystems.

DETAILED DESCRIPTION

The disclosure relates generally to intravascular blood filters used tocapture foreign particles. In some embodiments the blood filter is adual-filter system to trap foreign bodies to prevent them from travelinginto the subject's right and left common carotid arteries. The filtersystems described herein can, however, be used to trap particles inother blood vessels within a subject, and they can also be used outsideof the vasculature. The systems described herein are generally adaptedto be delivered percutaneously to a target location within a subject,but they can be delivered in any suitable way, and need not be limitedto minimally-invasive procedures.

In one application, the filter systems described herein are used toprotect the cerebral vasculature against embolisms and other foreignbodies entering the bloodstream during a cardiac valve replacement orrepair procedure. To protect both the right common carotid artery andthe left common carotid artery during such procedures, the systemdescribed herein enters the aorta from the brachiocephalic artery. Oncein the aortic space, there is a need to immediately navigate a 180degree turn into the left common carotid artery. In gaining entry intothe aorta from the brachial cephalic artery, use of prior art catheterdevices 1 will tend to hug the outer edge of the vessel 2, as shown inFIG. 1. To then gain access to the left common carotid artery 3 withsuch prior art devices can be a difficult maneuver due to the closeproximity of the two vessels which may parallel one another, oftenwithin 1 cm of separation, as shown in, for example, FIGS. 1-5. Thissharp turn requires a very small radius and may tend to kink thecatheter reducing or eliminating a through lumen to advance accessoriessuch as guidewires, filters, stents, and other interventional tools. Thecatheter-based filter systems described herein can traverse this ratherabrupt 180 degree turn to thereby deploy filters to protect both theright and left common carotid arteries.

FIGS. 1A and 1B illustrate a portion of an exemplary filter system.Filter system 10 includes proximal sheath 12, proximal shaft 14 coupledto expandable proximal filter 16, distal shaft 18 coupled to distalarticulatable sheath 20, distal filter 22, and guiding member 24. FIG.1A illustrates proximal filter 16 and distal filter 22 in expandedconfigurations. FIG. 1B illustrates the system in a deliveryconfiguration, in which proximal filter 16 (not seen in FIG. 1B) is in acollapsed configuration constrained within proximal sheath 12, whiledistal filter 22 is in a collapsed configuration constrained withindistal articulatable sheath 20.

FIG. 1C is a sectional view of partial system 10 from FIG. 1B. Proximalshaft 14 is co-axial with proximal sheath 12, and proximal region 26 ofproximal filter 16 is secured to proximal shaft 14. In its collapsedconfiguration, proximal filter 16 is disposed within proximal sheath 12and is disposed distally relative to proximal shaft 14. Proximal sheath12 is axially (distally and proximally) movable relative to proximalshaft 14 and proximal filter 16. System 10 also includes distal sheath20 secured to a distal region of distal shaft 18. Distal shaft 18 isco-axial with proximal shaft 14 and proximal sheath 12. Distal sheath 20and distal shaft 18, secured to one another, are axially movablerelative to proximal sheath 12, proximal shaft 14 and proximal filter16. System 10 also includes distal filter 22 carried by guiding member24. In FIG. 1C, distal filter 22 is in a collapsed configuration withindistal sheath 22. Guiding member 24 is coaxial with distal sheath 20 anddistal shaft 18 as well as proximal sheath 12 and proximal shaft 14.Guiding member 24 is axially movable relative to distal sheath 20 anddistal shaft 18 as well as proximal sheath 12 and proximal shaft 14.Proximal sheath 12, distal sheath 20, and guiding member 24 are eachadapted to be independently moved axially relative to one other. Thatis, proximal sheath 12, distal sheath 20, and guiding member 24 areadapted for independent axial translation relative to each of the othertwo components.

In the embodiments in FIGS. 1A-1E, proximal filter 16 includes supportelement or frame 15 and filter element 17, while distal filter 22includes support element 21 and filter element 23. The support elementsgenerally provide expansion support to the filter elements in theirrespective expanded configurations, while the filter elements areadapted to filter fluid, such as blood, and trap particles flowingtherethrough. The expansion supports are adapted to engage the wall ofthe lumen in which they are expanded. The filter elements have porestherein that are sized to allow the blood to flow therethrough, but aresmall enough to prevent unwanted foreign particles from passingtherethrough. The foreign particles are therefore trapped by and withinthe filter elements.

In one embodiment of the construction of the filter elements, filterelement 17 is formed of a polyurethane film mounted to frame 15, asshown in FIGS. 1D and 1E. Film element 17 can measure about 0.0030inches to about 0.0003 inches in thickness. Filter element 17 hasthrough holes 27 to allow fluid to pass and will resist the embolicmaterial within the fluid. These holes can be circular, square,triangular or other geometric shapes. In the embodiment as shown in FIG.1D, an equilateral triangular shape would restrict a part larger than aninscribed circle but have an area for fluid flow nearly twice as largemaking the shape more efficient in filtration verses fluid volume. It isunderstood that similar shapes such as squares and slots would provide asimilar geometric advantage.

Frame element 15 can be constructed of a shape memory material such asNitinol, stainless steel or MP35N or a polymer that has suitablematerial properties. Frame element 15 could take the form of a roundwire or could also be of a rectangular or elliptical shape to preserve asmaller delivery profile. In one such embodiment, frame element 15 is ofNitinol wire where the hoop is created from a straight piece of wire andshape set into a frame where two straight legs run longitudinally alongthe delivery system and create a circular distal portion onto which thefilter film will be mounted. The circular portion may have a radiopaquemarking such as a small coil of gold or platinum iridium forvisualization under fluoroscopy.

In some embodiments, such as those illustrated in FIGS. 1D, 1E and 25D,the shape of frame element 15 and filter element 17 are of an obliquetruncated cone having a non-uniform or unequal length around and alongthe length of the conical filter 16. In such a configuration, much likea windsock, the filter 16 would have a larger opening diameter and areduced ending diameter. In one embodiment, the larger opening diametercould measure about 15-20 mm in diameter and have a length of about30-50 mm. Varying size filters would allow treatment of variable patientvessel sizes.

It some embodiments the material of the filter element is a smoothtextured surface that is folded or contracted into a small deliverycatheter by means of tension or compression into a lumen. Areinforcement fabric 29, as shown in FIG. 1E, may be added to orembedded in the filter to accommodate stresses placed on the filtermaterial by means of the tension or compression applied. This will alsoreduce the stretching that may occur during delivery and retraction offilter element 17. This reinforcement material 29 could be a polymer ormetallic weave to add additional localized strength. This material couldbe imbedded into the polyurethane film to reduce its thickness. In oneparticular embodiment, this imbedded material could be polyester weavewith a pore size of about 100 microns and a thickness of about 0.002inches and mounted to a portion of the filter near the longitudinalframe elements where the tensile forces act upon the frame and filtermaterial to expose and retract the filter from its delivery system.While such an embodiment of the filter elements has been described forconvenience with reference to proximal filter element 17, it isunderstood that distal filter element 23 could similarly take such formor forms.

As shown in FIG. 1A, proximal filter 16 has a generally distally-facingopening 13, and distal filter 22 has a generally proximally-facingopening 19. The filters can be thought of as facing opposite directions.As described in more detail below, the distal sheath is adapted to besteered, or bent, relative to the proximal sheath and the proximalfilter. As the distal sheath is steered, the relative directions inwhich the openings face will be adjusted. Regardless of the degree towhich the distal sheath is steered, the filters are still considered tohaving openings facing opposite directions. For example, the distalsheath could be steered to have a 180 degree bend, in which case thefilters would have openings facing in substantially the same direction.The directions of the filter openings are therefore described if thesystem were to assume a substantially straightened configuration, anexample of which is shown in FIG. 1A. Proximal filter element 17 tapersdown in the proximal direction from support element 15, while distalfilter element 23 tapers down in the distal direction from supportelement 21. A fluid, such as blood, flows through the opening and passesthrough the pores in the filter elements, while the filter elements areadapted to trap foreign particles therein and prevent their passage to alocation downstream to the filters.

In some embodiments the filter pores are between about 1 micron and 1000microns (1 mm). The pore size can be larger, however, depending on thelocation of the filter within the subject and the type of particulatebeing trapped in the filter.

The filters are secured to separate system components. In the embodimentin FIGS. 1A-1C, for example, proximal filter 16 is secured to proximalshaft 14, while distal filter 22 is secured to guiding member 24. InFIGS. 1A-1C, the filters are secured to independently-actuatablecomponents. This allows the filters to be independently controlled.Additionally, the filters are collapsed within two different tubularmembers in their collapsed configurations. In the embodiment in FIGS.1A-1C, for example, proximal filter 16 is collapsed within proximalsheath 12, while distal filter 22 is collapsed within distal sheath 20.In the system's delivery configuration, the filters are axially-spacedfrom one another. For example, in FIG. 1C, distal filter 22 isdistally-spaced relative to proximal filter 16.

In some embodiments the distal sheath and the proximal sheath havesubstantially the same outer diameter (see, e.g., FIGS. 1B and 1C). Whenthe filters are collapsed within the sheaths, the sheath portion of thesystem therefore has a substantially constant outer diameter, which canease the delivery of the system through the patient's body and increasethe safety of the delivery. In FIG. 1C, distal and proximal sheaths 20and 12 have substantially the same outer diameter, both of which havelarger outer diameters than the proximal shaft 14. Proximal shaft 14 hasa larger outer diameter than distal shaft 18, wherein distal shaft 18 isdisposed within proximal shaft 14. Guiding member 24 has a smallerdiameter than distal shaft 18. In some embodiments the proximal anddistal sheaths have an outer diameter of 6 French (F). In someembodiments the sheaths have different outer diameters. For example, theproximal sheath can have a size of 6 F, while the distal sheath has asize of 5 F. In an alternative embodiment the proximal sheath is 5 F andthe distal sheath is 4 F. A distal sheath with a smaller outer diameterthan the proximal sheath reduces the delivery profile of the system andcan ease delivery.

In some methods of use, the filter system is advanced into the subjectthrough an incision made in the subject's right radial artery. In avariety of medical procedures a medical instrument is advanced through asubject's femoral artery, which is larger than the right radial artery.A delivery catheter used in femoral artery access procedures has alarger outer diameter than would be allowed in a filter system advancedthrough a radial artery. Additionally, in some uses the filter system isadvanced from the right radial artery into the aorta via thebrachiocephalic trunk. The radial artery has the smallest diameter ofthe vessels through which the system is advanced. The radial arterytherefore limits the size of the system that can be advanced into thesubject when the radial artery is the access point. The outer diametersof the systems described herein, when advanced into the subject via aradial artery, are therefore smaller than the outer diameters of theguiding catheters (or sheaths) typically used when access is gained viaa femoral artery.

FIG. 6A illustrates a portion of a filter delivery system in a deliveryconfiguration. The system's delivery configuration generally refers tothe configuration when both filters are in collapsed configurationswithin the system. FIG. 6B illustrates that that the distal articulatingsheath is independently movable with 3 degrees of freedom relative tothe proximal sheath and proximal filter. In FIG. 6A, proximal sheath 60and distal sheath 62 are coupled together at coupling 61. Coupling 61can be a variety of mechanisms to couple proximal sheath 60 to distalsheath 62. For example, coupling 61 can be an interference fit, afriction fit, a spline fitting, or any other type of suitable couplingbetween the two sheaths. When coupled together, as shown in FIG. 6A, thecomponents shown in FIG. 6B move as a unit. For example, proximal sheath60, proximal shaft 64, proximal filter 66, distal shaft 68, and thedistal filter (not shown but within distal sheath 62) will rotate andtranslate axially (in the proximal or distal direction) as a unit. Whenproximal sheath 60 is retracted to allow proximal filter 66 to expand,as shown in FIG. 6B, distal sheath 62 can be independently rotated(“R”), steered (“S”), or translated axially T (either in the proximal“P” direction or distal “D” direction). The distal sheath therefore has3 independent degrees of freedom: axial translation, rotation, andsteering. The adaptation to have 3 independent degrees of freedom isadvantageous when positioning the distal sheath in a target location,details of which are described below.

FIGS. 2A-2D illustrate a merely exemplary embodiment of a method ofusing any of the filter systems described herein. System 10 from FIGS.1A-1C is shown in the embodiment in FIGS. 2A-2D. System 10 is advancedinto the subject's right radial artery through an incision in the rightarm. The system is advanced through the right subclavian artery and intothe brachiocephalic trunk 11, and a portion of the system is positionedwithin aorta 9 as can be seen in FIG. 2A (although that which is shownin FIG. 2A is not intended to be limiting). Proximal sheath 12 isretracted proximally to allow proximal filter support element 15 toexpand to an expanded configuration against the wall of thebrachiocephalic trunk 11, as is shown in FIG. 2B. Proximal filterelement 17 is secured either directly or indirectly to support element15, and is therefore reconfigured to the configuration shown in FIG. 2B.The position of distal sheath 20 can be substantially maintained whileproximal sheath 12 is retracted proximally. Once expanded, the proximalfilter filters blood traveling through the brachiocephalic artery 11,and therefore filters blood traveling into the right common carotidartery 7. The expanded proximal filter is therefore in position toprevent foreign particles from traveling into the right common carotidarterty 7 and into the cerebral vasculature. Distal sheath 20 is thensteered, or bent, and distal end 26 of distal sheath 20 is advanced intothe left common carotid artery 13, as shown in FIG. 2C. Guiding member24 is thereafter advanced distally relative to distal sheath 20,allowing the distal support element to expand from a collapsedconfiguration against the wall of the left common carotid artery 13 asshown in FIG. 2D. The distal filter element is also reconfigured intothe configuration shown in FIG. 2D. Once expanded, the distal filterfilters blood traveling through the left common carotid artery 13. Thedistal filter is therefore in position to trap foreign particles andprevent them from traveling into the cerebral vasculature.

Once the filters are in place and expanded, an optional medicalprocedure can then take place, such as a replacement heart valveprocedure. Any plaque dislodged during the heart valve replacementprocedure that enters into the brachiocephalic trunk or the left commoncarotid artery will be trapped in the filters.

The filter system can thereafter be removed from the subject (or at anypoint in the procedure). In an exemplary embodiment, distal filter 22 isfirst retrieved back within distal sheath 20 to the collapsedconfiguration. To do this, guiding member 24 is retracted proximallyrelative to distal sheath 20. This relative axial movement causes distalsheath 20 to engage strut 28 and begin to move strut 28 towards guidingmember 24. Support element 21, which is coupled to strut 28, begins tocollapse upon the collapse of strut 28. Filter element 23 thereforebegins to collapse as well. Continued relative axial movement betweenguiding member 24 and distal sheath 20 continues to collapse strut 28,support element 21, and filter element 23 until distal filter 22 isretrieved and re-collapsed back within distal sheath 20 (as shown inFIG. 2C). Any foreign particles trapped within distal filter element 23are contained therein as the distal filter is re-sheathed. Distal sheath20 is then steered into the configuration shown in FIG. 2B, and proximalsheath is then advanced distally relative to proximal filter 16. Thiscauses proximal filter 16 to collapse around distal shaft 18, trappingany particles within the collapsed proximal filter. Proximal sheath 12continues to be moved distally towards distal sheath 20 until in theposition shown in FIG. 2A. The entire system 10 can then be removed fromthe subject.

An exemplary advantage of the systems described herein is that thedelivery and retrieval system are integrated into the same catheter thatstays in place during the procedure. Unloading and loading of differentcatheters, sheaths, or other components is therefore unnecessary. Havinga system that performs both delivery and retrieval functions alsoreduces procedural complexity, time, and fluoroscopy exposure time.

FIGS. 7A-7B illustrate a perspective view and sectional view,respectively, of a portion of an exemplary filter system. The systemincludes distal shaft 30 and distal articulatable sheath 34, coupled viacoupler 32. FIG. 7B shows the sectional view of plane A. Distal sheath34 includes steering element 38 extending down the length of the sheathand within the sheath, which is shown as a pullwire. The pullwire canbe, for example without limitation, stainless steel, MP35N®, or any typeof cable. Distal sheath 34 also includes spine element 36, which isshown extending down the length of the sheath on substantially theopposite side of the sheath from steering element 38. Spine element 36can be, for example without limitation, a ribbon or round wire. Spineelement 36 can be made from, for example, stainless steel or nitinol.Spine element 36 provides axial stiffness upon the application of anactuating force applied to steering element 38, allowing sheath 34 to besteered toward configuration 40, as shown in phantom in FIG. 7A. FIG. 7Cshows an alternative embodiment in which distal sheath 33 has anon-circular cross section. Also shown are spine element 35 and steeringelement 37.

FIGS. 8A-8C illustrate views of exemplary pullwire 42 that can beincorporated into any distal sheaths described herein. Plane B in FIG.8B shows a substantially circular cross-sectional shape of pullwire 42in a proximal portion 44 of the pullwire, while plane C in FIG. 8C showsa flattened cross-sectional shape of distal portion 46. Distal portion46 has a greater width than height. The flattened cross-sectional shapeof distal portion 46 provides for an improved profile, flexibility, andresistance to plastic deformation, which provides for improvedstraightening.

FIGS. 9, 9A, and 9B show an alternative embodiment of distal sheath 48that includes slots 50 formed therein. The slots can be formed by, forexample, grinding, laser cutting or other suitable material removal fromdistal sheath 48. The characteristics of the slots can be varied tocontrol the properties of the distal sheath. For example, the pitch,width, depth, etc., of the slots can be modified to control theflexibility, compressibility, torsional responsiveness, etc., of distalsheath 48. More specifically, the distal sheath 48 can be formed from alength of stainless steel hypotubing. Transverse slots 50 are preferablyformed on one side of the hypotubing.

FIG. 9B shows a further embodiment of the distal sheath in greaterdetail. In this embodiment distal sheath 48 includes a first proximalarticulatable hypotube section 49. Articulatable hypotube section 49 isfixed to distal shaft 30 (not shown in FIG. 9B). A second distalarticulatable section 51 is secured to first proximal section 49. Pullwire 38 extends from the handle to both distal shaft sections 49 and 51.This embodiment allows for initial curvature of distal sheath proximalsection 49 away from the outer vessel wall. Distal sheath distal section51 is then articulated to a second curvature in the opposite direction.This second curvature of distal shaft section 51 is adjustable basedupon tension or compression loading of the sheath section by pull wire38.

As shown in FIG. 9B, pull wire 38 crosses to an opposite side of theinner lumen defined by sections 49 and 51 as it transitions from thefirst proximal distal sheath section 49 to distal sheath distal section51. As best shown in FIG. 9C, distal sheath proximal section 49 wouldarticulate first to initialize a first curve. And, as the tension onpull wire 38 is increased, distal sheath distal section 51 begins tocurve in a direction opposite to the direction of the first curve, dueto pull wire 38 crossing the inner diameter of the lumen through distalsheath sections 49 and 51. As can be seen in FIG. 9C, as it nears andcomes to the maximum extent of its articulation, distal sheath distalsection 51 can take the form of a shepherd's staff or crook.

Distal sheath proximal section 49 could take the form of a tubularslotted element or a pre-shaped curve that utilizes a memory materialsuch as Nitinol. Distal sheath proximal section 49, in one particularembodiment, measures about 0.065 inches in diameter with an about 0.053inch hole through the center and measures about 0.70 inches in length.It is understood that these sizes and proportions will vary depending onthe specific application and those listed herein are not intended to belimiting. Transverse slots 50 can measure about 0.008 inches in widthbut may vary from about 0.002 inches to about 0.020 inches depending onthe specific application and the degree of curvature desired. In oneembodiment distal shaft proximal section 49 is a laser cut tube intendedto bend to approximately 45 degrees of curvature when pull wire 38 isfully tensioned. This curvature may indeed be varied from about 15degrees to about 60 degrees depending upon the width of slots 50. It mayalso bend out-of-plane to access more complex anatomy. This out-of-planebend could be achieved by revolving the laser cut slots rotationallyabout the axis of the tube or by bending the tube after the lasercutting of the slots. The shape could also be multi-plane orbidirectional where the tube would bend in multiple directions withinthe same laser cut tube.

Distal sheath distal section 51 is preferably a selectable curve basedupon the anatomy and vessel location relative to one another. Thissection 51 could also be a portion of the laser cut element or aseparate construction where a flat ribbon braid could be utilized. Itmay also include a stiffening element or bias ribbon to resist permanentdeformation. In one embodiment it would have a multitude of flat ribbonsstaggered in length to create a constant radius of curvature underincreased loading.

FIGS. 10A and 10B illustrate a portion of exemplary distal sheath 52that is adapted to be multi-directional, and is specifically shown to bebi-directional. Distal sheath 52 is adapted to be steered towards theconfigurations 53 and 54 shown in phantom in FIG. 10A. FIG. 10B is asectional view in plane D, showing spinal element 55 and first andsecond steering elements 56 disposed on either side of spinal element55. Steering elements 56 can be similar to steering element 38 shown inFIG. 7B. The steering elements can be disposed around the periphery ofdistal sheath at almost any location.

Incorporating steerable functionality into tubular devices is known inthe area of medical devices. Any such features can be incorporated intothe systems herein, and specifically into the articulatable distalsheaths.

In some embodiments the distal sheath includes radiopaque markers tovisualize the distal sheath under fluoroscopy. In some embodiments thedistal sheath has radiopaque markers at proximal and distal ends of thesheath to be able to visualize the ends of the sheath.

An exemplary advantage of the filter systems described herein is theability to safely and effectively position the distal sheath. In someuses, the proximal filter is deployed in a first bodily lumen, and thedistal filter is deployed in a second bodily lumen different than thefirst. For example, as shown in FIG. 2D, the proximal filter is deployedin the brachiocephalic trunk and the distal filter is deployed in a leftcommon carotid artery. While both vessels extend from the aortic arch,the position of the vessel openings along the aortic arch varies frompatient-to-patient. That is, the distance between the vessel openingscan vary from patient to patient. Additionally, the angle at which thevessels are disposed relative to the aorta can vary from patient topatient. Additionally, the vessels do not necessarily lie within acommon plane, although in many anatomical illustrations the vessels aretypically shown this way. For example, FIGS. 11A-11C illustrate merelyexemplary anatomical variations that can exist. FIG. 11A is a top view(i.e., in the superior-to-inferior direction) of aorta 70, showingrelative positions of brachiocephalic trunk opening 72, left commoncarotid artery opening 74, and left subclavian opening 76. FIG. 11B is aside sectional view of aortic 78 illustrating the relative angles atwhich brachiocephalic trunk 80, left common carotid artery 82, and leftsubclavian artery 84 can extend from aorta 78. FIG. 11C is a sidesectional view of aorta 86, showing vessel 88 extending from aorta 86 atan angle. Any or all of the vessels extending from aorta 86 could beoriented in this manner relative to the aorta. FIGS. 11D and 11Eillustrate that the angle of the turn required upon exiting thebrachiocephalic trunk 92/100 and entering the left common carotid artery94/102 can vary from patient to patient. Due to the patient-to-patientvariability between the position of the vessels and their relativeorientations, a greater amount of control of the distal sheath increasesthe likelihood that the distal filter will be positioned safely andeffectively. For example, a sheath that only has the ability toindependently perform one or two of rotation, steering, and axialtranslation may not be adequately adapted to properly and safelyposition the distal filter in the left common carotid artery. All threedegrees of independent motion as provided to the distal sheathsdescribed herein provide important clinical advantages. Typically, butwithout intending to be limiting, a subject's brachiocephalic trunk andleft carotid artery are spaced relatively close together and are eithersubstantially parallel or tightly acute (see, e.g., Figure BE).

FIGS. 12A and 12B illustrates an exemplary curvature of a distal sheathto help position the distal filter properly in the left common carotidartery. In FIGS. 12A and 12B, only a portion of the system is shown forclarity, but it can be assumed that a proximal filter is included, andin this example has been expanded in brachiocephalic trunk 111. Distalshaft 110 is coupled to steerable distal sheath 112. Distal sheath 112is steered into the configuration shown in FIG. 12B. The bend created indistal sheath 112, and therefore the relative orientations of distalsheath 112 and left common carotid artery 113, allow for the distalfilter to be advanced from distal sheath 112 into a proper position inleft common carotid 113. In contrast, the configuration of distal sheath114 shown in phantom in FIG. 12A illustrates how a certain bend createdin the distal sheath can orient the distal sheath in such a way that thedistal filter will be advanced directly into the wall of the left commoncarotid (depending on the subject's anatomy), which can injure the walland prevent the distal filter from being properly deployed. Depending onthe angulation, approach angle, spacing of the openings, etc., a generalU-shaped curve (shown in phantom in FIG. 12A) may not be optimal forsteering and accessing the left common carotid artery from thebrachiocepahlic trunk.

In some embodiments the distal sheath is adapted to have a preset curvedconfiguration. The preset configuration can have, for example, a presetradius of curvature (or preset radii of curvature at different pointsalong the distal sheath). When the distal sheath is articulated to besteered to the preset configuration, continued articulation of thesteering element can change the configuration of the distal sheath untilis assumes the preset configuration. For example, the distal sheath cancomprise a slotted tube with a spine extending along the length of thedistal sheath. Upon actuation of the steering component, the distalsheath will bend until the portions of the distal sheath that define theslots engage, thus limiting the degree of the bend of the distal sheath.The curve can be preset into a configuration that increases thelikelihood that the distal filter will, when advanced from the distalsheath, be properly positioned within the left common carotid artery.

FIGS. 13A and 13B illustrate alternative distal sheath and distal shaftportions of an exemplary filter system. FIGS. 13A and 13B only showdistal shaft 120 and distal sheath 122 for clarity, but the system alsoincludes a proximal filter (not shown but has been deployed inbrachiocephalic trunk). The distal shaft/distal sheath combination has ageneral S-bend configuration, with distal shaft 120 including a firstbend 124 in a first direction, and distal sheath 122 configured toassume bend 126 in a second direction, wherein the first and secondbends form the general S-bend configuration. FIG. 13B shows distalsheath 122 pulled back in the proximal direction relative to theproximal filter to seat the curved distal sheath against the bend. Thisboth helps secure the distal sheath in place as well as reduces thecross sectional volume of the filter system that is disposed with theaorta. The distal shaft and distal sheath combination shown in FIGS. 13Aand 13B can be incorporated into any of the filter systems describedherein.

Exemplary embodiments of the delivery and deployment of a multi-filterembolic protection apparatus will now be described with reference toFIGS. 2A-2D, 13A, 13B, 14, 1, 3, 4 and 5. More particularly, thedelivery and deployment will be described with reference to placement ofthe filter system in the brachiocephalic and left common carotidarteries. The preferred access for the delivery of the multi-filtersystem 10 is from the right radial or right brachial artery. The systemis then advanced through the right subclavian artery to a positionwithin the brachiocephalic artery 11. At this point, proximal filter 16may be deployed within into expanding engagement with the inner liningof brachiocephalic artery 11. Alternatively, access to the left commoncarotid could be gained prior to deployment of proximal filter 16.Deployment of proximal filter 16 protects both the brachiocephalicartery 11 and the right common carotid artery 7 against emboli and otherforeign bodies in the bloodstream.

Entry into the aortic space, as illustrated in FIG. 3, is thenaccomplished by further advancement of the system from thebrachiocephalic trunk. During this step, the filter system will tend tohug the outer portion of the brachiocephalic trunk as shown in FIG. 4.Initial tensioning of pull wire 38 causes distal sheath 48 to move thecatheter-based filter system off the wall of the brachiocephalic arteryjust before the ostium or entrance into the aorta, as shown in FIG. 4.As the catheter path will hug the outer wall of the brachial cephalicartery, a curve directed away from this outer wall will allow additionalspace for the distal portion of the distal sheath to curve into the leftcommon carotid artery, as shown in FIG. 5.

The width of slots 50 will determine the amount of bending allowed bythe tube when tension is applied via pull wire 38. For example, a narrowwidth slot would allow for limited bending where a wider slot wouldallow for additional bending due to the gap or space removed from thetube. As the bending is limited by the slot width, a fixed shape orcurve may be obtained when all slots are compressed and touching oneanother. Additional features such as chevrons may be cut into the tubeto increase the strength of the tube when compressed. Theses chevronswould limit the ability of the tube to flex out of the preferred planedue to torsional loading. Other means of forming slots could be obtainedwith conventional techniques such as chemical etching, welding ofindividual elements, mechanical forming, metal injection molding orother conventional methods.

Once in the aortic space, the distal sheath is further tensioned toadjust the curvature of the distal shaft distal section 51, as shown inFIG. 9C. The amount of deflection is determined by the operator of thesystem based on the particular patient anatomy.

Other techniques to bias a catheter could be external force applicationsto the catheter and the vessel wall such as a protruding ribbon or wirefrom the catheter wall to force the catheter shaft to a preferredposition within the vessel. Flaring a radial element from the cathetercentral axis could also position the catheter shaft to one side of thevessel wall. Yet another means would be to have a pull wire external tothe catheter shaft exiting at one portion and reattaching at a moredistal portion where a tension in the wire would bend or curve thecatheter at a variable rate in relation to the tension applied.

This multi-direction and variable curvature of the distal sheath allowsthe operator to easily direct the filter system, or more particularly,the distal sheath section thereof, into a select vessel such as the leftcommon carotid artery or the left innominate artery. Furthermore, thefilter system allows the operator to access the left common carotidartery without the need to separately place a guidewire in the leftcommon carotid artery. The clinical variations of these vessels are animportant reason for the operator to have a system that can accessdiffering locations and angulations between the vessels. The filtersystems described herein will provide the physician complete controlwhen attempting to access these vessels.

Once the distal sheath is oriented in the left common carotid, thehandle can be manipulated by pulling it and the filter system into thebifurcation leaving the aortic vessel clear of obstruction foradditional catheterizations, an example of which is shown in FIG. 12B.At this time, distal filter 22 can be advanced through proximal shaft 14and distal shaft 18 into expanding engagement with left common carotidartery 13.

FIG. 14 illustrates a portion of an exemplary system including distalshaft 130 and distal sheath 132. Distal sheath is adapted to be able tobe steered into what can be generally considered an S-bendconfiguration, a shepherd's staff configuration, or a crookconfiguration, comprised of first bend 131 and second bend 133 inopposite directions. Also shown is rotational orb 134, defined by theouter surface of the distal sheath as distal shaft 130 is rotated atleast 360 degrees in the direction of the arrows shown in FIG. 14. If atypical aorta is generally in the range from about 24 mm to about 30 mmin diameter, the radius of curvature and the first bend in the S-bendcan be specified to create a rotational orb that can reside within theaorta (as shown in FIG. 14), resulting in minimal interference with thevessel wall and at the same time potentially optimize access into theleft common carotid artery. In other distal sheath and/or distal shaftdesigns, such as the one shown in FIG. 12A, the rotational orb createdby the rotation of distal shaft 110 is significantly larger, increasingthe risk of interference with the vessel wall and potentially decreasingthe access into the left common carotid artery. In some embodiments, thediameter of the rotation orb for a distal sheath is less than about 25mm.

Referring back to FIG. 12A, distal sheath 112, in some embodiments,includes a non-steerable distal section 121, an intermediate steerablesection 119, and a proximal non-steerable section 117. When the distalsheath is actuated to be steered, only steerable portion 119 bends intoa different configuration. That is, the non-steerable portions retainsubstantially straight configurations. The distal non-steerable portionremains straight, which can allow the distal filter to be advanced intoa proper position in the left common carotid artery.

While FIG. 12A shows distal sheath 112 in a bent configuration, thedistal sheath is also positioned within the lumen of the aorta. In thisposition, the distal sheath can interfere with any other medical deviceor instrument that is being advanced through the aorta. For example, inaortic valve replacement procedures, delivery device 116, with areplacement aortic valve disposed therein, is delivered through theaorta as shown in FIG. 12B. If components of the filter system aredisposed within the aorta during this time, delivery device 116 and thefilter system can hit each other, potentially damaging either or bothsystems. The delivery device 116 can also dislodge one or both filtersif they are in the expanded configurations. The filter system canadditionally prevent the delivery device 116 from being advanced throughthe aorta. To reduce the risk of contact between delivery device 116 anddistal sheath 112, distal sheath 112 (and distal shaft 110) istranslated in the proximal direction relative to the proximal filter(which in this embodiment has already been expanded but is not shown),as is shown in FIG. 12B. Distal sheath 112 is pulled back until theinner curvature of distal sheath 112 is seated snugly with thevasculature 15 disposed between the brachiocephalic trunk 111 and theleft common carotid artery 113. This additional seating step helpssecure the distal sheath in place within the subject, as well asminimize the amount of the filter system present in the aortic arch.This additional seating step can be incorporated into any of the methodsdescribed herein, and is an exemplary advantage of having a distalsheath that has three degrees of independent motion relative to theproximal filter. The combination of independent rotation, steering, andaxial translation can be clinically significant to ensure the distalfilter is properly positioned in the lumen, as well as making sure thefilter system does not interfere with any other medical devices beingdelivered to the general area inside the subject.

An additional advantage of the filter systems herein is that the distalsheath, when in the position shown in FIG. 11C, will act as a protectionelement against any other medical instruments being delivered throughthe aorta (e.g., delivery device 116). Even if delivery device 116 wereadvanced such that it did engage distal sheath 112, distal sheath 112 isseated securely against tissue 15, thus preventing distal sheath 112from being dislodged. Additionally, distal sheath 112 is stronger than,for example, a wire positioned within the aorta, which can easily bedislodged when hit by delivery device 16.

FIGS. 15A-15D illustrate alternative embodiments of the coupling of thedistal shaft and distal sheath. In FIG. 15A distal shaft 140 is securedto distal sheath 142 by coupler 144. Shaft 140 has a low profile toallow for the collapse of the proximal filter (see FIG. 1C). Shaft 140also has column strength to allow for axial translation, has sufficienttorque transmission properties, and is flexible. The shaft can have asupport structure therein, such as braided stainless steel. For example,the shaft can comprise polyimide, Polyether ether ketone (PEEK), Nylon,Pebax, etc. FIG. 15B illustrates an alternative embodiment showingtubular element 146, distal shaft 148, and distal sheath 150. Tubularelement 146 can be a hypotube made from stainless steel, nitinol, etc.FIG. 15C illustrates an exemplary embodiment that includes distal shaft152, traction member 154, and distal sheath 156. Traction member 154 iscoupled to shaft 152 and shaft 152 is disposed therein. Traction member154 couples to shaft 152 for torquebility, deliverability, anddeployment. Traction member 154 can be, for example without limitation,a soft silicone material, polyurethane, or texture (e.g., polyimide,braid, etc.). FIG. 15D shows an alternative embodiment in which thesystem includes bushing 162 disposed over distal shaft 158, whereindistal shaft 158 is adapted to rotate within bushing 162. The systemalso includes stop 160 secured to distal shaft 158 to substantiallymaintain the axial position of bushing 162. When the system includesbushing 162, distal sheath 164 can be rotated relative to the proximalsheath and the proximal filter when the distal sheath and proximalsheath are in the delivery configuration (see FIG. 1B).

FIG. 16 illustrates an exemplary embodiment of filter system 170 inwhich distal sheath 172 is biased to a curved configuration 174. Thebiased curved configuration is adapted to facilitate placement,delivery, and securing at least the distal filter. As shown, the distalsheath is biased to a configuration that positions the distal end of thedistal sheath towards the left common carotid artery.

FIG. 17 illustrates a portion of an exemplary filter system and itsmethod of use. FIG. 17 shows a system and portion of deployment similarto that shown in FIG. 2D, but distal sheath 182 has been retractedproximally relative to guiding member 190 and distal filter 186. Distalsheath 182 has been retracted substantially from the aortic arch and issubstantially disposed with the brachiocephalic trunk. Guiding member190 can have preset curve 188 adapted to closely mimic the anatomicalcurve between the brachiocephalic trunk and the left common carotidartery, thus minimizing the amount of the system that is disposed withinthe aorta. As shown, distal sheath 182 has been retracted proximallyrelative to proximal filter 180.

FIG. 18A is a perspective view of a portion of an exemplary embodimentof a filter system, while FIG. 18B is a close-up view of a portion ofthe system shown in FIG. 18A. The distal sheath and the distal filterare not shown in FIGS. 18A and 18B for clarity. The system includesproximal filter 200 coupled to proximal shaft 202, and push rod 206coupled to proximal shaft 202. A portion of proximal sheath 204 is shownin FIG. 18A in a retracted position, allowing proximal filter 200 toexpand to an expanded configuration. Only a portion of proximal sheath204 is shown, but it generally extends proximally similar to push rod206. The proximal end of proximal shaft 202 is beveled and defines anaspiration lumen 216, which is adapted to receive an aspirator (notshown) to apply a vacuum to aspirate debris captured within distallyfacing proximal filter 200. Push rod 206 extends proximally withinproximal sheath 204 and is coupled to an actuation system outside of thesubject, examples of which are described below. Push rod 206 takes upless space inside proximal sheath 204 than proximal shaft 202, providinga lower profile.

The system also includes proximal seal 214 disposed on the outer surfaceof proximal shaft 202 and adapted to engage the inner surface of theproximal sheath. Proximal seal 214 prevents bodily fluids, such asblood, from entering the space between proximal sheath 204 and proximalshaft 202, thus preventing bodily fluids from passing proximally intothe filter system. The proximal seal can be, for example withoutlimitation, a molded polymer. The proximal seal can also be machined aspart of the proximal shaft, such that they are not considered twoseparate components.

In some specific embodiments the push rod is about 0.015 inches indiameter, and is grade 304 stainless steel grade. The proximal shaft canbe, for example without limitation, an extruded or molded plastic, ahypotube (e.g., stainless steel), machined plastic, metal, etc.

Proximal filter 200 includes filter material 208, which comprises poresadapted to allow blood to pass therethrough, while debris does not passthrough the pores and is captured within the filter material. Proximalfilter 200 also includes strut 210 that extends from proximal shaft 202to expansion support 212. Expansion support 212 has a generally annularshape but that is not intended to be limiting. Proximal filter 200 alsohas a leading portion 220 and a trailing portion 222. Leading portion220 generally extends further distally than trailing portion 222 to givefilter 200 a generally canted configuration relative to the proximalshaft. The canted design provides for decreased radial stiffness and abetter collapsed profile. Strut 210 and expansion support 212 generallyprovide support for filter 200 when in the expanded configuration, asshown in FIG. 18A.

FIGS. 19A-19C illustrate exemplary embodiments of proximal filters andproximal shafts that can be incorporated into any of the systems herein.In FIG. 19A, filter 230 has flared end 232 for improved filter-wallopposition. FIG. 19B shows proximal shaft 244 substantially co-axialwith vessel 246 in which filter 240 is expanded. Vessel 246 and shaft244 have common axis 242. FIG. 19B illustrates longitudinal axis 254 ofshaft 256 not co-axial with axis 252 of lumen 258 in which filter 250 isexpanded.

FIGS. 20A and 20B illustrate an exemplary embodiment including proximalfilter 260 coupled to proximal shaft 262. Filter 260 includes filtermaterial 264, including slack material region 268 adapted to allow thefilter to collapse easier. Filter 260 is also shown with at least onestrut 270 secured to shaft 262, and expansion support 266. As shown inthe highlighted view in FIG. 20B, filter 260 includes seal 274,radiopaque coil 276 (e.g., platinum), and support wire 278 (e.g.,nitinol wire). Any of the features in this embodiment can be included inany of the filter systems described herein.

FIG. 21 illustrates an exemplary embodiment of a proximal filter.Proximal filter 280 is coupled to proximal shaft 282. Proximal filter280 includes struts 286 extending from proximal shaft 282 to strutrestraint 288, which is adapted to slide axially over distal shaft 284.Proximal filter 280 also includes filter material 290, with porestherein, that extends from proximal shaft 282 to a location axiallybetween proximal shaft 282 and strut restraint 288. Debris can passthrough struts 286 and become trapped within filter material 290. Whenproximal filter 280 is collapsed within a proximal sheath (not shown),struts 286 elongate and move radially inward (towards distal shaft 284).Strut restraint 288 is adapted to move distally over distal shaft 284 toallow the struts to move radially inward and extend a greater lengthalong distal shaft 284.

FIGS. 22A and 22B illustrate an exemplary embodiment of a proximalfilter that can be incorporated into any filter system described herein.The system includes proximal filter 300 and proximal sheath 302, shownin a retracted position in FIG. 22A. Proximal filter 300 includes valveelements 304 in an open configuration in FIG. 22A. When valve elements304 are in the open configuration, foreign particles 306 can passthrough opening 308 and through the valve and become trapped in proximalfilter 300, as is shown in FIG. 22A. To collapse proximal filter 300,proximal sheath 302 is advanced distally relative to proximal filter300. As the filter begins to collapse, the valve elements are broughtcloser towards one another and into a closed configuration, as shown inFIG. 22B. The closed valve prevents extrusion of debris during therecapture process.

The distal filters shown are merely exemplary and other filters may beincorporated into any of the systems herein. FIG. 23A illustrates aportion of an exemplary filter system. The system includes guidingmember 340 (distal sheath not shown), strut 342, expansion support 344,and filter element 346. Strut 342 is secured directly to guiding member340 and strut 342 is secured either directly or indirectly to expansionsupport 344. Filter material 346 is secured to expansion support 344.Distal end 348 of filter material 346 is secured to guiding member 340.

FIG. 23B illustrates a portion of an exemplary filter system. The systemincludes guiding element 350, strut support 352 secured to guidingelement 350, strut 354, expansion support 356, and filter material 358.Strut support 352 can be secured to guiding element 350 in any suitablemanner (e.g., bonding), and strut 354 can be secured to strut support352 in any suitable manner.

FIG. 23C illustrates a portion of an exemplary filter system. The systemincludes guiding element 360, strut support 362 secured to guidingelement 360, strut 364, expansion support 366, and filter material 368.Expansion support 366 is adapted to be disposed at an angle relative tothe longitudinal axis of guiding member 360 when the distal filter is inthe expanded configuration. Expansion support 366 includes trailingportion 362 and leading portion 361. Strut 364 is secured to expansionsupport 366 at or near leading portion 361. FIG. 23D illustrates anexemplary embodiment that includes guiding member 370, strut support372, strut 374, expansion support 376, and filter material 378.Expansion support 376 includes leading portion 373, and trailing portion371, wherein strut 374 is secured to expansion element 376 at or neartrailing portion 371. Expansion support 376 is disposed at an anglerelative to the longitudinal axis of guiding member 370 when the distalfilter is in the expanded configuration.

FIG. 23E illustrates an exemplary embodiment of a distal filter in anexpanded configuration. Guiding member 380 is secured to strut support382, and the filter includes a plurality of struts 384 secured to strutsupport 382 and to expansion support 386. Filter material 388 is securedto expansion support 386. While four struts are shown, the distal filtermay include any number of struts.

FIG. 23F illustrates an exemplary embodiment of a distal filter in anexpanded configuration. Proximal stop 392 and distal stop 394 aresecured to guiding member 390. The distal filter includes tubular member396 that is axially slideable over guiding member 390, but is restrictedin both directions by stops 392 and 394. Strut 398 is secured toslideable member 396 and to expansion support 393. Filter material 395is secured to slideable member 396. If member 396 slides axiallyrelative to guiding member 390, filter material 395 moves as well.Member 396 is also adapted to rotate in the direction “R” relative toguiding member 390. The distal filter is therefore adapted toindependently move axially and rotationally, limited in axialtranslation by stops 392 and 394. The distal filter is therefore adaptedsuch that bumping of the guiding member or the distal sheath will notdisrupt the distal filter opposition, positioning, or effectiveness.

FIGS. 24A-24C illustrate exemplary embodiments in which the systemincludes at least one distal filter positioning, or stabilizing, anchor.The positioning anchor(s) can help position the distal anchor in aproper position and/or orientation within a bodily lumen. In FIG. 24Athe system includes distal filter 400 and positioning anchor 402. Anchor402 includes expandable stent 404 and expandable supports 406. Supports406 and filter 400 are both secured to the guiding member. Anchor 402can be any suitable type of expandable anchor, such as, for examplewithout limitation, stent 404. Anchor 402 can be self-expandable,expandable by an expansion mechanism, or a combination thereof. In FIG.24A, stent 404 can alternatively be expanded by an expansion balloon.Anchor 402 is disposed proximal to filter 400. FIG. 24B illustrates anembodiment in which the system includes first and second anchors 412 and414, one of which is proximal to filter 410, while the other is distalto filter 410. FIG. 24C illustrates an embodiment in which anchor 422 isdistal relative to filter 420.

In some embodiments the distal filter is coupled, or secured, to aguiding member that has already been advanced to a location within thesubject. The distal filter is therefore coupled to the guiding memberafter the distal filter has been advanced into the subject, rather thanwhen the filter is outside of the subject. Once coupled together insidethe subject, the guiding member can be moved (e.g., axially translated)to control the movement of the distal filter. In some embodiments theguiding member has a first locking element adapted to engage a secondlocking element on the distal filter assembly such that movement of theguiding member moves the distal filter in a first direction. In someembodiments the distal filter assembly has a third locking element thatis adapted to engage the first locking element of the guiding membersuch that movement of the guiding member in a second direction causesthe distal filter to move with the guiding member in the seconddirection. The guiding member can therefore be locked to the distalfilter such that movement of the guiding member in a first and a seconddirection will move the distal filter in the first and seconddirections.

By way of example, FIGS. 25A-25D illustrate an exemplary embodiment ofcoupling the distal filter to a docking wire inside of the subject,wherein the docking wire is subsequently used to control the movement ofthe distal filter relative to the distal sheath. In FIG. 25A, guidecatheter 440 has been advanced through the subject until the distal endis in or near the brachiocephalic trunk 441. A docking wire, comprisinga wire 445, locking element 442, and tip 444, has been advanced throughguide catheter 440, either alone, or optionally after guiding wire 446has been advanced into position. Guiding wire 446 can be used to assistin advancing the docking wire through guide catheter 440. As shown, thedocking wire has been advanced from the distal end of guide catheter440. After the docking wire is advanced to the desired position, guidecatheter 440, and if guiding wire 446 is used, are removed from thesubject, leaving the docking wire in place within the subject, as shownin FIG. 25B. Next, as shown in FIG. 25C, the filter system, includingproximal sheath 448 with a proximal filter in a collapsed configurationtherein (not shown), distal sheath 450, with a distal filter assembly(not shown) partially disposed therein, is advanced over wire 445 untila locking portion of the distal filter (not shown but described indetail below) engages locking element 442. The distal filter assemblywill thereafter move (e.g., axially) with the docking wire. Proximalsheath 448 is retracted to allow proximal filter 454 to expand (see FIG.25D). Distal sheath 450 is then actuated (e.g., bent, rotated, and/ortranslated axially) until it is in the position shown in FIG. 25D. Astraightened configuration of the distal sheath is shown in phantom inFIG. 25D, prior to bending, proximal movement, and/or bending. Thedocking wire is then advanced distally relative to distal sheath 450,which advances distal filter 456 from distal sheath 450, allowing distalfilter 456 to expand inside the left common carotid artery, as shown inFIG. 25D.

FIGS. 26A-26D illustrate an exemplary method of preparing an exemplarydistal filter assembly for use. FIG. 26A illustrates a portion of thefilter system including proximal sheath 470, proximal filter 472 is anexpanded configuration, distal shaft 474, and articulatable distalsheath 476. Distal filter assembly 478 includes an elongate member 480defining a lumen therein. Elongate member 480 is coupled to distal tip490. Strut 484 is secured both to strut support 482, which is secured toelongate member 480, and expansion support 486. Filter element 488 haspores therein and is secured to expansion support 486 and elongatemember 480. To load distal filter assembly 478 into distal sheath 476,loading mandrel 492 is advanced through distal tip 490 and elongatemember 480 and pushed against distal tip 490 until distal filterassembly 478 is disposed within distal sheath 476, as shown in FIG. 26C.Distal tip 490 of the filter assembly remains substantially distal todistal sheath 476, and is secured to the distal end of distal sheath476. Distal tip 490 and distal sheath 476 can be secured together by africtional fit or other type of suitable fit that disengages asdescribed below. Loading mandrel 492 is then removed from the distalfilter and distal sheath assembly, as shown in FIG. 26D.

FIG. 26E illustrates docking wire 500 including wire 502, lock element504, and distal tip 506. Docking wire 500 is first advanced to a desiredposition within the subject, such as is shown in FIG. 25B. The assemblyfrom FIG. 26D is then advanced over docking wire, wherein distal tip 490is first advanced over the docking wire. As shown in the highlightedview in FIG. 26F, distal tip 490 of the distal filter assembly includesfirst locking elements 510, shown as barbs. As the filter/sheathassembly continues to be distally advanced relative to the docking wire,the docking wire locking element 504 pushes locks 510 outward in thedirection of the arrows in FIG. 26F. After lock 504 passes locks 510,locks 510 spring back inwards in the direction of the arrows shown inFIG. 26G. In this position, when docking wire 500 is advanced distally(shown in FIG. 26F), lock element 504 engages with lock elements 510,and the lock element 504 pushes the distal filter assembly in the distaldirection. In this manner the distal filter can be distally advancedrelative to the distal sheath to expand the distal filter. Additionally,when the docking wire is retracted proximally, locking element 504engages the distal end 512 of elongate member 480 and pulls the distalfilter in the proximal direction. This is done to retrieve and/orrecollapse the distal filter back into the distal sheath after it hasbeen expanded.

FIGS. 27A and 27B illustrate an exemplary embodiment in which guidingmember 540, secured to distal filter 530 before introduction into thesubject is loaded into articulatable distal sheath 524. The system alsoincludes proximal filter 520, proximal sheath 522, and distal shaft 526.FIG. 27B shows the system in a delivery configuration in which bothfilters are collapsed.

FIGS. 28A-28E illustrate an exemplary distal filter assembly incollapsed and expanded configurations. In FIG. 28A, distal filterassembly 550 includes a distal frame, which includes strut 554 andexpansion support 555. The distal frame is secured to floating anchor558, which is adapted to slide axially on elongate member 564 betweendistal stop 560 and proximal stop 562, as illustrated by the arrows inFIG. 28A. The distal filter assembly also includes membrane 552, whichhas pores therein and is secured at its distal end to elongate member564. The distal filter assembly is secured to a guiding member, whichincludes wire 566 and soft distal tip 568. The guiding member can be,for example, similar to the docking wire shown in FIGS. 26A-26E above,and can be secured to the distal filter assembly as described in thatembodiment.

The floating anchor 558 allows filter membrane 552 to return to aneutral, or at-rest, state when expanded, as shown in FIG. 28A. In itsneutral state, there is substantially no tension applied to the filtermembrane. The neutral deployed state allows for optimal filter frameorientation and vessel apposition. In the neutral state shown in FIG.28A, floating anchor 558 is roughly mid-way between distal stop 560 andproximal stop 562, but this is not intended to be a limiting positionwhen the distal filter is in a neutral state.

FIG. 28B illustrates the distal filter being sheathed into distal sheath572. During the sheathing process, the distal filter is collapsed froman expanded configuration (see FIG. 28A) towards a collapsedconfiguration (see FIG. 28C). In FIG. 28B, distal sheath 572 is movingdistally relative to the distal filter. The distal end of the distalsheath 572 engages with strut 554 as it is advanced distally, causingthe distal end of strut 554 to moves towards elongate member 564. Strut554 can be thought of as collapsing towards elongate member 564 from theconfiguration shown in FIG. 28A. The force applied from distal sheath572 to strut 554 collapses the strut, and at the same time causesfloating anchor 558 to move distally on tubular member 564 towardsdistal stop 560. In FIG. 28B, floating anchor 558 has been moveddistally and is engaging distal stop 560, preventing any further distalmovement of floating anchor 558. As strut 554 is collapsed by distalsheath 572, strut 554 will force the attachment point between strut 554and expansion support 555 towards tubular member 564, beginning thecollapse of expansion support 555. Distal sheath 172 continues to beadvanced distally relative to the distal filter (or the distal filter ispulled proximally relative to the distal sheath, or a combination ofboth) until the distal filter is collapsed within distal sheath 172, asis shown in FIG. 28C. Filter membrane 552 is bunched to some degree whenthe filter is in the configuration shown in FIG. 28C. To deploy thedistal filter from the sheath, guiding member 566 is advanced distallyrelative to the distal sheath (or the distal sheath is moved proximallyrelative to the filter). The distal portions of filter membrane 552 andexpansion support 555 are deployed first, as is shown in FIG. 28D.Tension in the filter membrane prevents wadding and binding during thedeployment. When strut 554 is deployed from the distal sheath, expansionsupport 555 and strut 554 are able to self-expand to an at-restconfiguration, as shown in FIG. 28E. Floating anchor 558 is pulled inthe distal direction from the position shown in FIG. 28D to the positionshown in FIG. 28E due to the expansion of strut 554.

FIGS. 29A-29E illustrate a portion of an exemplary filter system with alower delivery and insertion profile. In FIG. 29A, the system includesproximal sheath 604 with a larger outer diameter than distal sheath 602.In some embodiments proximal sheath 604 has a 6 F outer diameter, whiledistal sheath 602 has a 5 F outer diameter. A guiding member includingdistal tip 606 is disposed within the distal sheath and the proximalsheath. FIG. 29B illustrates tear-away introducer 608, with receivingopening 610 and distal end 612. Introducer is first positioned within asubject with receiving opening 610 remaining outside the patient. Asshown in FIG. 29C, the smaller diameter distal sheath is first advancedthrough the receiving opening of introducer 608 until the distal end ofthe distal sheath is disposed distal relative to the distal end of theintroducer. The introducer is then split apart and removed from thesubject, as shown in FIG. 29D. The filter system can then be advanceddistally through the subject. The introducer can be a 5 F introducer,which reduces the insertion and delivery profile of the system.

The embodiments in FIGS. 25A-25B above illustrated some exemplarysystems and methods for routing filter systems to a desired locationwithin a subject, and additional exemplary embodiments will now bedescribed. FIGS. 30A and 30B illustrate an exemplary embodiment similarto that which is shown in FIGS. 27A and 27B. The filter system showsdistal filter 650 and proximal filter 644 in expanded configurations.Proximal sheath 642 has been retracted to allow proximal filter 644 toexpand. Distal filter, which is secured to guiding member 648, are bothadvanced distally relative to distal articulating sheath 640. The filtersystem does not have a dedicated guidewire that is part of the system,but distal sheath 640 is adapted to be rotated and steered to guide thesystem to a target location within the subject.

FIGS. 31A-31C illustrate an exemplary over-the-wire routing system thatincludes a separate distal port for a dedicated guidewire. A portion ofthe system is shown in FIG. 31A, including distal articulating sheath662 and proximal sheath 660 (the filters are collapsed therein). FIG.31B is a highlighted view of a distal region of FIG. 31A, showingguidewire entry port 666 near the distal end 664 of distal sheath 662.FIG. 31C is a sectional view through plane A of distal sheath 662,showing guidewire lumen 672, spine element 678, distal filter lumen 674,and steering element 676 (shown as a pullwire). Guidewire lumen 672 anddistal filter lumen 674 are bi-axial along a portion of distal sheath,but in region 670 guidewire lumen 672 transitions from within the wallof distal sheath 662 to being co-axial with proximal sheath 660.

To deliver the system partially shown in FIGS. 31A-31C, a guidewire isfirst delivered to a target location within the subject. The guidewirecan be any type of guidewire, such as a 0.014 inch coronary wire. Withthe guidewire in position, the proximal end of the guidewire is loadedinto guidewire entry port 666. The filter system is then tracked overthe guidewire to a desired position within the subject. Once the systemis in place, the guidewire is withdrawn from the subject, or it can beleft in place. The proximal and distal filters can then be deployed asdescribed in any of the embodiments herein.

FIGS. 32A-32E illustrate an exemplary routing system which includes arapid-exchange guidewire delivery. The system includes distalarticulating sheath 680 with guidewire entry port 684 and guidewire exitport 686. The system also includes proximal sheath 682, a distal filtersecured to a guiding member (collapsed within distal sheath 680), and aproximal filter (collapsed within proximal sheath 682). After guidewire688 is advanced into position within the patient, the proximal end ofguidewire 688 is advanced into guidewire entry port 684. Distal sheath(along with the proximal sheath) is tracked over guidewire 688 untilguidewire 688 exits distal sheath 680 at guidewire exit port 686.Including a guidewire exit port near the entry port allows for only aportion of the guidewire to be within the sheath(s), eliminating theneed to have a long segment of guidewire extending proximally from thesubject's entry point. As soon as the guidewire exits the exit port, theproximal end of the guidewire and the proximal sheath can both behandled. FIG. 32B shows guidewire 688 extending through the guidewirelumen in the distal sheath and extending proximally from exit port 686.Guidewire 688 extends adjacent proximal sheath 682 proximal to exit port686. In FIG. 32B, portion 690 of proximal sheath 682 has a diameterlarger than portion 692 to accommodate the proximal filter therein.Portion 692 has a smaller diameter for easier passage of the proximalsheath and guidewire. FIG. 32C shows a sectional view through plane A,with guidewire 688 exterior and adjacent to proximal sheath 682.Proximal filter 694 is in a collapsed configuration within proximalsheath 682, and guiding member 696 is secured to a distal filter, bothof which are disposed within distal shaft 698. FIG. 32D shows relativecross-sections of exemplary introducer 700, and distal sheath 680through plane CC. Distal sheath 680 includes guidewire lumen 702 anddistal filter lumen 704. In some embodiments, introducer 700 is 6 F,with an inner diameter of about 0.082 inches. In comparison, the distalsheath can have a guidewire lumen of about 0.014 inches and distalfilter lumen diameter of about 0.077 inches. In these exemplaryembodiments, as the distal sheath is being advanced through anintroducer sheath, the introducer sheath can tent due to the size andshape of the distal sheath. There may be some slight resistance to theadvancement of the distal sheath through the introducer sheath. FIG. 32Eshows a sectional view through plane B, and also illustrates theinsertion through introducer 700. Due to the smaller diameter of portion692 of proximal sheath 682, guidewire 688 and proximal sheath 682 moreeasily fit through introducer 700 than the distal sheath and portion ofthe proximal sheath distal to portion 692. Introducer is 6 F, whileproximal sheath is 5 F. Guidewire 688 is a 0.014 inch diameterguidewire. The smaller diameter proximal portion 692 of proximal sheath682 allows for optimal sheath and guidewire movement with the introducersheath.

FIG. 33 illustrates a portion of an exemplary filter system. The portionshown in FIG. 33 is generally the portion of the system that remainsexternal to the subject and is used to control the delivery andactuation of system components. Proximal sheath 710 is fixedly coupledto proximal sheath hub 712, which when advanced distally will sheath theproximal filter (as described herein), and when retracted proximallywill allow the proximal filter to expand. The actuation, or control,portion also includes handle 716, which is secured to proximal shaft714. When handle 716 is maintained axially in position, the position ofthe proximal filter is axially maintained. The actuation portion alsoincludes distal sheath actuator 722, which includes handle 723 anddeflection control 720. Distal sheath actuator 722 is secured to distalshaft 718. As described herein, the distal articulating sheath isadapted to have three independent degrees of motion relative to theproximal sheath and proximal filter: rotation, axially translation(i.e., proximal and distal), and deflection, and distal sheath actuator722 is adapted to move distal sheath 718 in the three degrees of motion.Distal sheath 718 is rotated in the direction shown in FIG. 33 byrotating distal sheath actuator 722. Axial translation of distal sheathoccurs by advancing actuator 722 distally (pushing) or by retractingactuator 722 proximally (pulling). Distal sheath 218 is deflected byaxial movement of deflection control 720. Movement of deflection control720 actuates the pullwire(s) within distal sheath 718 to control thebending of distal sheath 718. Also shown is guiding member 724, which issecured to the distal filter and is axially movable relative to thedistal sheath to deploy and collapse the distal filter as describedherein. The control portion also includes hemostasis valves 726, whichis this embodiment are rotating.

FIG. 34 illustrates an exemplary 2-piece handle design that can be usedwith any of the filter systems described herein. This 2-piece handledesign includes distal sheath actuator 746, which includes handlesection 748 and deflection control knob 750. Deflection control knob 750of distal sheath actuator 746 is secured to distal shaft 754. Axialmovement of distal sheath actuator 746 will translate distal shaft 754either distally or proximally relative to the proximal filter andproximal sheath. A pull wire (not shown in FIG. 34) is secured to handlesection 748 and to the distal articulatable sheath (not shown in FIG.34). Axial movement of deflection control knob 750 applies tension, orrelieves tension depending on the direction of axial movement ofdeflection control knob 750, to control the deflection of the distalarticulatable sheath relative to the proximal filter and proximal sheath744, which has been described herein. Rotation of distal sheath actuator746 will rotate the distal sheath relative to the proximal filter andproximal sheath. The handle also includes housing 740, in which proximalsheath hub 742 is disposed. Proximal sheath hub 742 is secured toproximal sheath 744 and is adapted to be moved axially to control theaxial movement of proximal sheath 744.

FIG. 35 illustrates another exemplary embodiment of a handle that can beused with any of the filter systems described herein. In this alternateembodiment the handle is of a 3-piece design. This 3-piece handle designcomprises a first proximal piece which includes distal sheath actuator761, which includes handle section 763 and deflection control knob 765.Deflection control knob 765 of distal sheath actuator 761 is secured todistal shaft 767. Axial movement of distal sheath actuator 761 willtranslate distal shaft 767 either distally or proximally relative to theproximal filter and proximal sheath. A pull wire (not shown in FIG. 35)is secured to handle section 763 and to the distal articulatable sheath(not shown in FIG. 35). Axial movement of deflection control knob 765applies tension, or relieves tension depending on the direction of axialmovement of deflection control knob 765, to control the deflection ofthe distal articulatable sheath relative to the proximal filter andproximal sheath 769. Rotation of distal sheath actuator 761 will rotatethe distal sheath relative to the proximal filter and proximal sheath769. The handle design further includes a second piece comprisingcentral section 760 which is secured to proximal shaft 771. A thirddistal piece of this handle design includes housing 762. Housing 762 issecured to proximal sheath 769. Housing 762 is adapted to move axiallywith respect to central section 760. With central section 760 held fixedin position, axial movement of housing 762 translates to axial movementof proximal sheath 769 relative to proximal shaft 771. In this manner,proximal filter 773 is either released from the confines of proximalsheath 769 into expandable engagement within the vessel or, depending ondirection of movement of housing 762, is collapsed back into proximalsheath 769.

While specific embodiments have been described herein, it will beobvious to those skilled in the art that such embodiments are providedby way of example only. Numerous variations, changes, and substitutionswill now occur to those skilled in the art without departing from thatwhich is disclosed. It should be understood that various alternatives tothe embodiments described herein may be employed in practicing thedisclosure.

1-74. (canceled)
 75. An intravascular blood filter system, comprising:an expandable filter assembly adapted to be collapsed within a deliverycatheter, the expandable filter assembly comprising: a frame adapted toengage a vessel wall when expanded; a filter element adapted to filterfluid, the filter element supported by the frame; and a reinforcementfabric provided to the filter element and configured to providelocalized strength.
 76. The filter system of claim 75, wherein thereinforcement fabric is mounted to the filter element.
 77. The filtersystem of claim 75, wherein the reinforcement fabric is embedded in thefilter element.
 78. The filter system of claim 75, wherein thereinforcement fabric reduces stretching that would otherwise occurwithout the reinforcement fabric.
 79. The filter system of claim 75,wherein the reinforcement fabric is a polymeric weave.
 80. The filtersystem of claim 75, wherein the reinforcement fabric is a metallicweave.
 81. The filter system of claim 75, wherein the frame comprises ahoop surrounding an opening of the expandable filter assembly.
 82. Thefilter system of claim 75, wherein the frame comprises a longitudinalframe element.
 83. The filter system of claim 82, wherein thereinforcement fabric is positioned near the longitudinal frame elementwhere tensile forces act on the frame.
 84. The filter system of claim75, wherein the frame comprises a radiopaque marking.
 85. The filtersystem of claim 75, wherein the filter assembly is an oblique truncatedcone.
 86. The filter system of claim 75, wherein the filter assembly hasa non-uniform length around the filter assembly.
 87. The filter systemof claim 75, wherein the filter element comprises polyurethane film. 88.The filter system of claim 75, wherein the frame comprises a shapememory material.